Printing telegraph system



5, 1939. c, Frrc 2,172,060

I PRINTING TELEGRAPH SYSTEM 7 Filed Dec. 4, 1937 7 Sheets -Sheet 1 27 JI lNVE T I H E0 ATTORNEY Sept. 5, 1939. FITC 2, 0

A PRINTING TELEGRAPH SYSTEM Filed Dec. 4, 1937 7 Sheets-Sheei 4'llll-llllw m n "lll-llljl In FIG. 2

1. 1| up mus ill-ll llL ATTORNEY p 5', c. J FITCH I PRINTING TELEGRAPHsYs'rz'u 7 Sheets-Sheet 5 Filed Dec. 4, 193'! VEN 4W ATTORNEY Sept. 5,1939. c, J F|TH 2,172,050

PRINTING TELEGRAPH SYSTEM Filed Dec. 4, 19137 7 Sheets-Sheet e ATTORN EYSept. 5, 1939.' c. J. FITCH PRINTING TELEGRAPH SYSTEM 7 Sheets-Sheet 7Filed Dec. 4, 1937 m Fri. v

lli I lu WHHHHI I H w BW L MI II .l llll LIIII w r l mi l nwT PatentedSept. 5, 1939 UNl'lED STATES- PATENT OFFICE 2,172,060 i PRINTINGTELEGRAPH SYSTEM Clyde J. Fitch, Endlcott, N. Y., ,assignor gmIntel-national Business Machines Corporation, New York, N. Y., acorporation of New York Application December 4, 1937, Serial No. 178,016

10 Claims. (01. 178-25) This invention relates to printing telegraphsystems and more particularly to novel means embodied therein to effectselection of a particular. group of printing instrumentalities from aplurality of such groups.

More specifically, the illustration of the principles of thepresentinvention is shown to embody a standard form of typewritingmechanism wherein the printing instrumentalities comprise typebarshaving two types, one for lower and the other for upper case printingand associated mechanism to effect shifting of the typebars relativelyto the platen for changing case. The said latter mechanism being ofknown construction whereby upon depression of the controlling shiftkeybar the type basket is shifted to upper case position and returned tolower case position, when the keybar is released; and it is -thereforecustomary to hold the-key depressed while writing upper case characters.

It has been proposed heretofore to provide control means so that uponsuccessive reception of control signals the said means is effective toalter the positioning of the type basket and thereby effect the desiredselection of the printing instrumentalities. In the present invention itis proposed to utilize a single control Signal, the transmission ofwhich is prolonged as long as the printing of the selected group ofinstrumentalities is desired, that is, the control or shiftsignal isapplied continuously to the control circuits as long, for example, asupper case printing is desired to be effected."

It is, therefore, an object of the present invention to provide meanswhereby control signals are applied continuously to a transmissionmedium in contradistinction to the aperiodic character signals.

Another object of the present invention is to provide means to maintainthe control contacts operated continuously during a desired controlperiod, whereas the character control contacts are operatedaperiodically during the said control period.

Another object of the invention is to provide means whereby theinitiation of the control signals are under control of the shiftdetermining means.

Further objects of the instant invention reside in any novel feature ofconstruction or operation or novel combination of parts present in theembodiment of the invention described and shown in the accompanyingdrawingswhether 5 within or without the scope of the appended claims andirrespective of other specific statements as, to the scope of theinvention contained herein.

In the drawings 10 Fig. 1 is a sectional view of one standard type oftypewriting mechanism.

Fig. 2 is an exploded view of certain control elements; the structuralfeatures of which are exaggerated to show clearly the normal operating15 positions thereof.

Fig. 3 is a transverse sectional view of the shifting mechanism of theillustrated typewriter.

Fig. 3a is a detail view of the type basket shift control cam.

' Fig. 4 is a sectional view of one type of signal control means.

Figs. 5 and 6 are detail views showing the mechanism in Fig. 4 inoperated positions.

Fig. 7 is a plan view of the mechanism shown in Fig. 4,

Fig. 8 is a sectional view of one type. of signal receiving permutationmechanism.

Fig. 9 is a perspective view of the control elements shown in Fig. 8. 30

Figs. 10 and 11 are detail views of the clutch unit.

Fig. 12 is aplan view of the mechanism shown in Fig. 8.

Fig. 13 is a diagrammatic circuit arrangement 35 of a suitable phasetransformer.

Fig. 14 is a circuit diagram of a single control circuit of the signalgenerator.

Fig. 15 is a circuit diagram showing a complete signal generator andsignal receiving system suitable for printing telegraph systems.

For illustrative purposes, this invention is shown as embodying a wellknown type of recording unit, which may be similar in construction tothe Electromatic typewriter, shown and described in detail in U. S.Patent No. 1,777,055, and hence requires only the following briefdescription.

Referring to the drawings and particularly to Fig. 1, well known meansare provided for actuating the typebars I6, comprising a constantlyrotating roller l0, cooperating with a series of individual power unitseach comprising a cam H, the engagement of the cams with the roller ,5;

being controlled selectively by the character keybars 11.

Any suitable means may be provided to rotate the power roller, in thedirection indicated by the arrow, which is adapted to cooperate with tworows of cam units arranged in the front and rear of the roller. The camH may be provided to be pivoted on,one arm of a bell crank lever 12which is pivoted in the frame of the recording unit, as indicatedgenerally by reference character t3, the other arm of the said bellcrank lever is operatively connected with an arm of bell crank lever itby means of link it. Another arm of the said lever- I4 is connected tothe typebars it in a well known manner, so as to effect operation of thetypebars or any other suitable means connected to the bell crank leversupon selective operation of the controlling keybars H.

The pivoted bell crank lever II is operated by the associated cam Hwhenever the latter engages the driven roller; the engagement of the camwith the roller is controlled by means of the associated control keybarIll in a manner. which will now be briefly described.

Referring now to Fig. 2, the cams occupy normally the positions as shownin this figure, which represents one of the rear bank of the units. Inthis position the impeller-arm I8 is urged, by the associated coilspring l9. against one of the impeller-lugs 20, which at the time is inthe lower position, and tends to turn the cam H in a clockwisedirection. This is prevented, however, by the engagement of one of thedetents 2! on the cam, with the upper stop lug 2 2 on the stop lever 23.If, however, the corresponding keybar is operated, the bifurcated lowerend (Fig. l) of extension arm 24 associated with oneof the said keybarsl7 engages an arm 25 at the upper end of the stop lever 23 which isprovided with an offset projection at its end which extends laterallythrough an opening in the bell crank lever E2. The arm 25 of the stoplever 23 is then swung rearwardly or to the left as viewed in Fig. 1about the pivot 26 and its lower end forwardly or to the right as viewedin this figure, thus releasing the cam, which then turns under theinfluence of the springurged impeller-arm It. In doing so the upperserrated lobe of the cam is brought into engagement with the powerroller, which turns in a counterclockwise direction and therefore causesa continued rolling movement of the cam until the high point has beenreached and passed. This causes the .whole cam unit to swing around thepivot i3v so as to pull down the corresponding link and actuate one ofthe typebars or any other mechanism with which the cam unit may beconnected.

After the high point of the cam is passed the cam loses contact with theroller, but the said impeller-arm l8 tends to'continue the rotationthereof by engaging the second impeller-lug 29 of cam H until the seconddetent 21 engages one of the stop lugs. Since the half rotation of thecam consumes only a small fraction of a second, it is diflicult torelease the keybar within this short interval, so that it is the lowerlug 28 which is first engaged, but upon the release of the keybar andthe return of the stop lever 23 to normal position, this lug 28disengages the detent, whereupon the impeller-arm rotates the camslightly, and the said detent then engages the upper stop lug 22.

It is obvious then that depression of a keybar releases the revolublymounted cam to engage and be actuated by the power roller in turnoperating the associated bell crank lever and its attached links tocause the associated mechanism such as the typebars and other operatingmechanisms to be operated. It is to be understood that an individual camunit is provided for each typebar or other functional mechanismsassociated therewith.

The action of the cam mechanism has been described with respect to oneof the rear bank of cam units; in the case of those of the forward bankthe operation is analogous, but the directions of movement, and theorder of operation of the stop lugs, is reversed. For example, if thebifurcated arm '24--a is positioned to engage the arm 25-0. at the upperend of stop lever 23-41 by virtue of operation of the associated keybar,the said arm' is positioned rearwardly or to the left as viewed in Fig.l, and the lower end 'of the stop lever 23-11 is moved forwardly, thatis, to the right as viewed in the said figure. This said operation iseffective to release the cam, by virtue of positioning the lower stoplug 28--a out of the path of detent 2 Ia, thus permitting thespringurged' impeller-arm l8--a. to rotate the cam slightly in aclockwise direction to effect engagement of the lower lobe of cam I land power roller. Upon completion of a half revolution of the cam i I,the second detent 21-41 engages first the upper stop lug 22-a while thestop lever 23-a is in an operated position, but upon release of theassociated keybar and the return of the said stop lever to normalposition, this lug 22--a disengages the said detent and the impeller-armrotates the cam slightly so that the said detent then engages the lowerstop lug 28-0,, as shown in the figure. In this manner the bell cranklever l2-u is rotated about the pivot I3a to operate the associatedtypebar or any other mechanism associated therewith. For furtherstructural details of the cam units, reference should be made to theabove mentioned patent.

Referring now to Figs. 3 and 3a., a brief description of the type basketshift mechanism employed in the said typewriter will now follow; for adetailed description of this known structure reference should be made toU. S. Patent No. 1,945,097. This mechanism comprises a movably mountedtype basket 30 upon which the typebars it are pivotally mounted forcooperation with the printing'point on the platen. Each of the typebarsl6 has two types 3|, one for lower and the other for upper caseprinting. With the parts in the normal position shown in the figure, thelower one of the types engages the platen for printing when the typebaris actuated, and upon shifting the type basket the other type engagesthe platen for printing.

-The type basket is resiliently supported and guided in its case shiftmovements on the free ends of the springs 32 and 33. Power actuated keycontrolled means are provided for shifting the type basket and comprisestwo toggles so arranged that one or the other is in its straightenedposition when the type basket is shifted to one or the other of itsprinting positions. One of said toggles comprises the link 34 pivoted atone end to a bracket 35 projecting rearwardly from the type basket. Theother end of link 34 is pivoted to an arm of bell crank lever 36 fixedto one end of rock shaft 31 which extends to the other side of the typebasket. The other arm of the bell crank lever 36 is connected with atoggle lever 38 by means of a link 39. By this arrangement the link 34and associated arm of bell crank 36 constitute in effect a toggle movedin its straight position when the type basket is in its upper or normalposition as shown inthe figure. The toggle lever 36 and link 39constitute in effect a second toggle movable from the broken positionshown to a straightened position. By means of the described togglearrangements the type basket is given either a downward or upwardmovement respectively, thus efiectingselection of a certain group ofinstrumentalities from a plurality of such groups.

Power driven key controlled means are provided for actuating saidtoggles to shift the type basket. This said means is similar to the camcontrol units described hereinabove, except, however, the detentarrangement on the double lobe cam, so

that the type basket may be shifted to upper and 42 projecting laterallytherefrom on opposite sides of its pivot, so that one or the other ofwhich is engaged by the spring urged impeller-arm 43 tending to turn thecam into engagement with the roller. The cam also has a pair oflaterally projecting detents 44 and 45 arranged on opposite sides 'ofand at different distances from its pivot and adapted to cooperate witha stop lug 46 provided on the lower end of stop lever 41.

It will be understood now, upon depression of the shift keybar 48, thatthe lower end of stop lever 41 is positioned to the right as viewed inthe figure, moving the stop lug 46 from the path of detent 44 and intothe path of detent 45, permitting the cam 49 to move into engagementwith the roller under the action of impeller-arm 43.

By depressing the keybar, and by the engagement of its arm 49 with theinterponent 50, therear end of the interponent is raised and maintainedin this position as long as the keybar is held depressed. The cam 46 isturned through one-half a revolution until its detent 45 moves intoengagement with the stop lug 46 on stop lever. During this movement ofthe cam the bell crank lever is tilted and swings arm 52 for-- wardlyand with it interponent 56, which by its position engages the lug 53 andswings the lever 38 about its pivot 54 to straighten the toggle 36 and39 and break the toggle 34 and 36, thus swinging the type basketdownwardly against the tension of the spring arms 32 and 33. A shiftlock mechanism 55 of known construction is shown to maintain the partsin the described position. Upon release of the shift keybar 46, the stoplever 41 is returned to the normal position shown in the figure,releasing detent 45 and positioning the stop lug 46 in the path ofdetent 43, so that again the cam 40 is rotated a half revolution. Theinterponent 50 is returned to the position shown in Fig. 3 when thekeybar is released, so that the cam during its rotation causes theinterponent 56 again to be actuated and engage the lug 56 on lever 38 toswing the lever to break its toggle 36 and 39 and at the same timestraighten the toggle 34 and 36 against the tension of springs 32 and 33to return the type basket to the normal lower case position.

When the described typewriter mechanism is used as a transmittingteleprinter embodying the present invention, the normally open contacts51 may be provided to be suitably positioned-and secured to the frame ofthe machine, so that the downward movement of the type basket 36 causesthe contacts to be closed, and opened when the basket is returned to thenormal lower case 'position. When employed as a teleprinter receiver,

suitable solenoid means 56, shown in the dotted section in the figure,may be provided to maintain the keybar depressed during .the period theupper case printing is desired to be effected. The purpose of thecontacts 51 and solenoid 56 will be understood as the descriptionprogresses. It is obviousfof course, that instead of printing upper andlower case characters upon shifting the type basket, any desired groupsof characters or signs can be provided on the type-bars, so that, whenthe basket is in the normal position shown, one of the groups ofcharacters are printed, and when shifted to the downward or lowerposition the other group of characters is printed. It is intended thatsuch modifications be encompassed in the scope of the present invention.

Referring now to Figs. 4 to 7, one method of conditioning andcontrolling signal generating means suitable for printing telegraphsystems is shown and is described in detail in the co-pendingapplication Serial No. 113,798, dated December 2,

1936. The bell crank levers l2 associated with the character keybars Hare provided with depending arms 59 supporting the cam rollers 60suitably positioned so as to displace the selector members 6|, when thecam units are released and mounted on suitable slotted guide bars 62secured to the frame of the typewriter unit. Each selector is providedwith equally spaced studs 63 alternately positioned on the selectors,for example, three on each of the sides of the selectors. which areadapted to engage fingers 64 selectively positioned on the permutationbars 65 rotatably mounted in a suitable frame. Certain of the fingers64extend above the'permutation bars 65 and others below the said bars. Thepurpose of this arrangement is described in detail in said applicationand need not be repeated here. The fingers and selectors are so arrangedthat upon displacement of the latter by the operation of the cam unitsthe fingers and associated bars are rotated in a counterclockwisedirection. In Figs. 5 and 6 certain of the selectors 6| are arranged sothat the studded section is engaged by the fingers 64 extending belowthe permutation bars and that these selectors are operated by theforward bank of cam units; and other selectors have the studs 63disposed so that they engage the fingers 64 extending above thepermutation bars so operated. The said selectors 6| are slidably' tionwill be given of one type of receiving perg mutation bar unit adapted tocontrol selectively the operation of the printing instrumentaiities.This said unit is described in the co-pending application Serial No.113,799, dated December 2, 1936, and comprises a plurality ofdifferently slotted permutation bars 68 suitably mounted in is driven bythe constantly rotating ratchet gear I3 by means of gears Id and 75operatively connected to the power roller by suitable means such as belt16. 5

Normally, the bars 68 are not operated in unison with the driving gear13, due to the stop 18 engaging the dog lift lever TI which maintainsthe toothed dog I8 in the position as shown in Fig. 9. However, uponenergization of the control magnet 19, the stop 76 is positioned out ofthe path of the pivoted dog lift lever ll, so that the spring 80 iseffective to urge the slidable dog 18 and lever 11 to the right asviewed in Fig. 9

to permit engagement of the tooth 8| on the dog I8 and ratchet gear 13,thus operating the permutation bar 68 and gear I8 in unison.

The signal energizing the magnet 19 lasts momentarily so that upondeenergization thereof, the stop 16 again is positioned in the path ofthe lever 11 so that upon engagement of the stop 16 by said lever thetoothed dog I8 is disengaged from the rotating gear 13. An individualclutch unit and associated magnet is provided for each permutation barso that upon the energization of the said magnets in variouscombinations, in accordance with a selected code, different combinationsof bars are rotated by the described clutch units to effect thealignment of the differently positioned slots on the permutation bars,thus permitting the levers 69 to be lowered in the aligned slots duringthe rotation of the bars. The said levers 69 by means of the links 10are then effective to lower the controlling keybars of the. typewriterto eifect recording of the characters corresponding to the receivedcharacter signalsby means of the described-power operated unitscontrolled by the associated keybars.

Referring now to Figs. 13 to 15, one type of signal transmitting andreceiving means is shown and is described in detail in the co-pendingapplication Serial No. 156,443, and dated December 7, 1934. Briefly, thecircuit arrangement shown in the said figures comprises a phasesplitting means to generate a plurality of outof-phase voltages andapplying the said voltages to individual control circuits, eachincluding electric discharge devices adapted to emit a series of shortsignal impulses equally spaced with respect to each other. The signalgenerating circuits may then be applied simultaneously to a transmissionmedium controlling a receiving system similar in operation to thetransmitting circuits.

In Fig. 13, a preferred type of phase-splitter 82 is shown to comprisetwo transformingmeans including the primary windings 83 and 84 and thecorresponding secondary windings 88-11 to 83-g and 84-11 to 8H. Acondenser 85 is provided in the primary circuit of one and an indicator86 in the primary circuit of the other, so that the voltages in saidcircuits are de grees out of phase and that the voltages across each ofthe primaries is the same. It is to be noted that the turns ratio of theindividual secondary windings vary for each phase connecelectricaldegrees apart, each phase of which is adapted to deliver equal voltagesacross the free ends of the secondary circuits. The describedphase-splitter is employed in both the trans-- mitting and receivingcircuits and indicated in these circuits generally by the referencecharacters 82-A and 82-B, respectively.

Referring to Fig. 14, anindividual tube circuit, which may be associatedwith any one of the secondary output circuits of the phasesplitter, willnow be described and is shown to comprise an electric discharge device'1' equivalent to a full wave rectifier and triode in one envelope andwhich is well known in the art, commonly referred to as a "duplex diodetriode type. The diode plates 81 are joined to the terminals of thesecondary winding of transformer 88 and the shunt connected resistor IS,the center tap of which is connected to the grid 90 of the device T andby means of resistor 0| is also joined to the cathode 92 thereof. The

control contacts il-a and transformer Ql-a areinserted in the outputcircuit of the device.

terminal of the battery. This described condi-' tion exists in thecircuit for only a. comparatively short time, because the bias on grid90 is no longer zero and is not a constant factor, but

varies in a timed relationship with the frequency of the A. 0. supplysource. The said supply source by means of transformer 88 is impressedupon the full wave rectifier section of the device and the rectifiedcurrent impressed upon resistor immediately drives the grid biasnegative with respect to the cathode. The value of the resistor 9| isadjusted so that, before the grid bias becomes effective to reduce theplate current to substantially zero value, a pulse is impressed upon theoutput circuit just traced so that a short signal impulse is impressedon the desired output circuit connected to the secondary winding oftransformer Sl-a. It is understood how that, if the contacts aremaintained in an operated position, a series of short equally spacedimpulses will be continuously impressed upon the said output circuit,and that the frequency of the initiated signals is twice the frequencyof the A. 0. supply source.

Referring now to Fig. 15, the operation of the signal generating andtransmitting circuits will now be understood; the individual electricdischarge devices T-l to T6 and associated cirsuits (the operation ofeach circuit and device precisely as just described) are connected tothe individual output circuits of the phase transforming means 82--A,several circuits are shown only in detail. The contacts 61 (Figs. 4 to6) included in the associated output circuits are connected in common tosignal transmitting means which may be one of any of the known types ofsignal transmitters. The said contacts 61 represent the signalconditioning or initiating means and may be operated in differentcombinations by the mechanism described hereinabove to initiate variouscombinations of out-of-phase impulses representing the charactersignals.

Upon operation of any of the contacts 51 singly condensers are theneffective or in different combinations equally spaced timed impulseswill be initiated, the timing of the outof-phase impulses with respectto each other is controlled by the phase displaced voltages impressedupon the input circuits of the electric discharge devices.

The controlled circuits just described related to phase associated withphases l to 6 of the phase-splitter. Phase I is not shown to be includedin the transmitting and receiving circuits; this phase may be used forother controlling purposes, not relevant to the present invention. Phase8 is connected to a circuit arrangement, including discharge device T-8,similar to the ones described, but is shown to be controlled by thecontacts 51, connected to the said common circuit, operated by the typebasket (Fig. 3), whenever shifted by the shift determining meansdescribed.

The receiving circuits includethe electric discharge devices R--l to R.6and R-8 and associated circuits which are similar to the transmittingcircuits are shown to be connected to a similar phase transforming means82--B connected to an A. C. supply source synchronous with the saidsupply source associated with the transmitting circuits- The individualanodes of the tubes are shown to be connected toa common circuit 96 to asource of plate potential, and the Y individual cathodes are connectedto the condensers C! to C-6 and C'8, respectively, which in turn areconnected to a common circuit 91 connected to the anode of control tube98 which is biased so that normally there is no current flow in itsoutput circuit, unless the received signal impulses are impressed on theinput circuit thereof. It will now be seen, upon reception of theout-of-phase signal impulses, tube 98 permits current to flow in itsoutput circuit so long'as the individual impulses are impressedthereupon. The circuits associated with the tubes R-I to Rr-6 and R-8are rendered operative in timed relationship with ,the operation of thecircuits associated with tubes T--I to T-6 and T--8 so that the receivedsignal impulses are in phase with the corresponding operated receivingcircuits, thereby permitting current to flow in the individualassociated cathode circuits including the condensers C-l to C-ii and C8and charging the corresponding condensers. For example, if the contacts61 for phases I and 6 were closed momentarily to initiate and cause thecorresponding signal impulses to be transmitted, upon reception of theseim pulses, the receiving circuits corresponding to phases I and 6thereat would be energized to charge the associated condensers C-l andC-6 to a predetermined voltage. The said charged to operate the normally biased tubes RT-l and RT-6 to energize the magnets 19 included inthe output circuits of the said tubes, The magnets 19 '(Figs. 8 to 12)associated with tubes RT-I to RT-B correspond to the receivingpermutation unit control magnets, thus operating the receiving recordingunit effecting recordingof the characters correspond ing to the receivedcharacter signal. It is to be noted that the magnet 58 (Fig. 3)associated with tube RT-B corresponds to the magnet describedhereinabove to operate the shift determining means of the receivingrecording unit. It should be mentioned that the charges on the grids ofthe tubes RT-l and RT6 and RT-8 are maintained so long as thetransmitting contacts are closed, and that due to the time constants ofthe condensers Cl to C-6 and C8 and the associated resistors theimpulses applied to the grids of the said tubes are relatively long,thereby delivering constant andsufiicient power to the said magnets.

The features of the present invention have now been described, and themethod and manner of practicing this invention should be evident fromthe disclosure just set forth; however, a brief summary of operation ofthe system will now be given.

Let it be assumed that the typewriting or recording units are operatedwith the type baskets in the normal positions, that is, with the shiftkeybar in the normal inoperative position, so that upon selectiveoperation of the character keybars I! at the transmitting unit thesignal initiating or conditioning means, namely, contacts 67, areoperated in different combinations or permutatively to operate thesignal generating means'accordingly, thus causing the combinations ofphase displaced impulses representing the character signals to beimpressed upon the transmission medium.

The combinations of out-of-phase impulses are impressed upon thereceiving circuits to charge the condensers CI to C 6 accordingly, thuscausing different combinations of the controlling magnets"!!! to beenergized, releasing the corre-, sponding permutation bars at thereceiving unitand operating the associated keybars to record thecharacters represented by the received character signals. In this mannerrecording of the characters of one. particular group is effected. Now,in order to effect printing of the characters in a different group, atany time during the transmission of the abovementioned character signalsthe shift keybar 48 is operated and by means of shift lock 55 can bemaintained in the said operated position for any desired period of time.While the shift keybar remains operated,

' the control contacts 51 are also maintained operative to initiatecontinuously the phase displaced control signals which are effective tocharge the condenser C8 at the receiver and cause the magnet 58 to beenergized constantly to depress the shift keybar at the receivingrecording unit to shift the type basket in a position to correspond tothe basket at the transmitting recording unit. Now, While the shiftcontrol contacts remain closed at the transmitting unit and while theshift control signals are continuously transmitted to maintain the shiftdetermining means at the receiver unit operative, the character keybarsi! are now operated selectively to initiate the phase displacedcharacter signals which are impressed upon the transmission medium sothat the corresponding groups of magnets 19 are energized to-effectrecording at the receiver from the other and different group of printinginstrumentalities. Printing from the first mentioned group ofinstrumentalities is effected again when the shift keybar at thetransmay be made by those skilled in the art without 15 departing fromthe spirit of the invention. It is .the intention therefore to belimited only as indicated by the scope of the following claims.

What is claimed is as follows:

1. In a system of the character described, a plurality of typewritingmechanisms, each having a positionable type basket and controllingkeybars therefor to position the basket from a normal position, signalcontrol means controlled by the positioned type basket of onetypewriting mechanism to initiate control signals as long as the typebasket is positioned from the said normal position, and means controlledby said signals to operate the controlling keybar of the othertypewriting mechanism to position the type basket thereof so as tocorrespond to the positioning of the type basket of the first mentionedmechanlsm.

2. In a system of the character described, a plurality of recordingunits, each having groups of printing instrumentalities shiftable todifferent positions and shifting control means for saidinstrumentalities, signal control means, controlled by said shiftingcontrol means when the printing-instrumentalities of one unit areshifted to effect printing of a certain group thereof, to initiatecontrol signals as long as said printing instrumentalities remain insaid shifted position, and means controlled by said signals to controlthe operation of the shifting control means of the other recording unitas long as the signals are initiated thereby maintaining the printinginstrumentalities of the last mentioned unit shifted to correspond tothose of the first said unit.

3. In a system of the character described, means to initiate controlsignals for a prolonged period, a remotely controlled recordingnnitcomprising shiftable printing instrumentalities and control meanstherefor, and means controlled by the said control signals to controlthe said control means as long as the signals are initiated, includingmeans for shifting the printing instrumentalities for a prolonged periodof time.

4. A system of the character described comprising means to transmitaperiodic character signals and means to initiate shift control signalscontinuously, recording means having shiftable printing:instrumentalities and control means therefor, means controlled by thecharacter signals to control the selective operation of the printinginstrumentalities, and means controlled by the shift signals to controlthe said control means to shift the printing instrumentalities andmaintain the printing instrumentalities in said shifted positionas longas the shift signals are initiated.

5. A system of the character described comprising means to initiateaperiodic character signals, shift determining means and meanscontrolled thereby to initiate shift control signals continuously,recording means having shiftable printing instrumentalities and controlmeans for the said instrumentalities and shift determining meanstherefor, means controlled by the aperiodic signals to control saidprinting instrumentalities control means selectively, and meanscontrolled by the shift signals to control the second said shiftdetermining means to shift the instrumen talities and maintain them inthe shifted position -as long as the shift signals are initiated.

6. A system of the character described comprising a plurality ofrecording units, each having printing means and a shiftable member forsaid printing means, means controlled by one of said units to initiateaperiodic character signals and means controlled by the shiftable memberthereof to initiate shift control signals continuously, means includedin another recording unit, controlled by the aperiodic signals tocontrol selectively the operation of the printing means, meanscontrolled by the continuously initiated shift signals to control theoperation of the shiftable member of the last mentioned recording unit,and means to maintain the said shiftable member operated as long as theshift signals are initiated.

7. A system of the character described comprising means to initiateaperiodic character signals and means to initiate periodic shift controlsignals, a recording unit having shiftable printing elements and meansto control the shifting thereof, means controlled by said aperiodicsignals to control selectively the operation of the printing elements,and means controlled by the periodic shift control signals to controlthe operation of said shifting control means including means formaintaining the last said means operative as long as the shift signalsare initiated.

8. A system of the character described comprising character controlcontacts operated aperiodicallyto initiate character signals and shiftcontrol contacts operated constantly to initiate shift signals, arecording unit having shiftable printing elements and means to controlthe shifting thereof, means controlled by the character signals tocontrol selectively the operation of the printing elements, and meanscontrolled by the shift signals to control the operation of the shiftingcontrol means including means for maintaining the last mentioned meansoperative as long as the shift signals are initiated.

9. A system of the character described comprising means to initiateaperiodic character signals, and means to initiate periodic controlsignals, a recording unit having shiftable printing elements and meansto control the shifting thereof, circuit means operated by the aperiodicsignals to control selectively the operation of the printing elements,and a. circuit including means whereby the circuit is operatedcontinuously by signals and means energized periodically by the signalsto control the operation of the shifting control means including meansfor effecting shifting of the printing elements as long as the said lastmentioned means is energized periodically.

CLYDE J. FITCH.

